Multi emissive layer type white organic light emitting diode based on zinc metal complexes

White organic light emitting diodes were fabricated using two zinc complexes bis(2-(2-hydroxyphenyl)benzoxazolato) zinc(II) [Zn(HPB)2] and bis(5,7-dimethyl-8-hydoxyquinolinato) zinc(II) [Zn(Me2q)2]. Zn(HPB)2 emitted light in blue region while Zn(Me2q)2 emitted light in orange region of the visible spectrum. Hence, we achieved white light by combining the two complimentary colors of the materials and by optimizing their thickness as emissive layer. Commission Internationale de l'Eclairage coordinates of the device, with 35 nm thickness of Zn(HPB)2 and 13 nm thickness of Zn(Me2q)2, were (0.28, 0.36) which were well within the white region. The device emitting white light showed maximum luminescence of 2582 cd/m2 at 19 V.

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